Liquid-cooled internal combustion engine with means for relieving thermal stress



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LIQUID-COOLEi) INTERNAL COMBUSTION ENGINE WITH MEANS FOR RELIEVINGTHERMAL STRESS Filed Oct. 5, 1959 13 Sheets-Sheet 1 6, 1962 c. L.STANCLIFF ETAI. 3,062,614

LIQUIDCOOLED INTERNAL COMBUSTION ENGINE WITH MEANS FOR RELIEVING THERMALSTRESS 1s Sheets-Sheet 2 Filed Oct. 5, 1959 7 a we IN V EN TORS CLlprolv L. firm/cuff 6:12am A firmvcurr Nov. 6, 1962 c. 1.. STANCLIFFETAL 3,062,614

LIQUID-COOLED INTERNAL COMBUSTION ENGINE WITH MEANS FOR RELIEVINGTHERMAL STRESS Filed Oct. 5, 1959 15 Sheets-Sheet a mfg I /Z I20 V l// IIIIIIIIIIII I w 7" /29 INVENTOR5 I42 2 H I, 5 CLIFTON LJMNcA/FF 13a 4652040 Mina/vaun- Nov. 6, 1962 c. L. STANCLIFF. ETAL 3,062,614

LIQUID-COOLED INTERNAL COMBUSTION ENGINE WITH MEANS FOR RELIEVINGTHERMAL STRESS Filed Oct. 5, 1959 15 Sheets-Sheet 4 Nov. 6, 1962 c. L.STANCLIFF ETAL 3,062,614

LIQU COOLED INTERNAL COMBUST ENGINE WITH EANS FOR RELIEVING THERM STRESSFiled Oct. 5, 1959 15 Sheets-Sheet 5 g mm /2 \& I /a/ M0 E st 10. 24. iI IIIIW mm ill? /6 aa I16. 224 CLIFTON l A fi'f BY V 9 m/ )./60 470 NM;

Nov. 6, 1962 c. STANCLIFF ETAL 3,062,614

LIQUID-COOLED INTERNAL COMBUSTION ENGINE WITH MEANS FOR RELIEVINGTHERMAL STRESS Filed Oct. 5, 1959 l5 Sheets-Sheet 6 IN VEN TORS CL mmvL. JTmVc'L/FF 652410 A 571mm m Nov. 6, 1962 c. STANCLIFF ET AL 3,

LIQUID-COOLED INTERNAL COMBUSTION ENGINE WITH MEANS FOR RELIEVINGTHERMAL STRESS l3 Sheets-Sheet 7 Filed Oct. 5, 1959 1962 c STANCLIFF ETAL 3,062,614

LIQUID-COOLED INTERNAL COMBUSTION ENGINE WITH MEANS FOR RELIEVINGTHERMAL STRESS Filed Oct. 5, 1959 15 Sheets-Sheet 8 l-lll lIm I-m III/IN VEN TORS CL IF MN .4. (firm/cu 652940 M firmvc; Mr

6, 1962 c STANCLIFF ETAL 3,062,614

LIQUID-COOLED INTERNAL COMBUSTION ENGINE WITH MEANS FOR RELIEVINGTHERMAL STRESS Filed Oct. 5, 1959 13 Sheets-Sheet 9 Era. 43.

IN V EN TOR5 62 IF 70M 1. 574mm; /F/' 652440 N 571mm; 1;;

0 IVE K5 NOV. 6, 1962 c. L. STANCLIFF ETA]. 3, 2,614

LIQUID-COOLED INTERNAL COMBUSTION ENGINE WITH MEANS FOR RELIEVINGTHERMAL STRESS Filed Oct. 5, 1959 l3 Sheets-Sheet l0 INVENTORS 61 MrmvZ. 5r4ua/FF Y 6:24.40 /1/ from; MP

c. L. STANCLIFF ETAL 3,062,614 LIQUID-COOLED INTERNAL COMBUSTION ENGINEWITH MEANS FOR RELIEVING THERMAL STRESS Nov. 6, 1962 15 Sheets-Sheet 11Filed Oct. 5, 1959 a 4 y d 5/ a 0 R/./ i ii w V a a N 5 a mum M f 2 midm Q N 4 0 ,Q/ 2 66 5 9 2 a an 7 2 6 Z n. 3 7 5 r a W My I w i u. 0 a w G4 I n a c. STANCLIFF ET AL 3,062,614 LIQUID-COOLED INTERNAL COMBUSTIONENGINE WITH MEANS FOR RELIEVING THERMAL STRESS Nov. 6, 1962 15Sheets-Sheet 12 Filed Oct. 5, 1959 United States Patent ()fiice3,062,614 Patented Nov. 6, 1962 3,962,614 LIQUID-(300L121) INTERNALCOMBUSTION EN- GlNE WITH MEANS FOR RELIEVING THERMAL STRESS Clifton L.Stancliif and Gerald N. Stanclilf, Bakersfield, Calif; said Gerald N.Stancliff assignor to said Clifton L. Stanclilf Filed Oct. 5, 1959, Ser.No. 844,367 30 Claims. (Cl. 123-41.01)

This invention relates generally to liquid-cooled internal combustionengines and, particularly, to improvements in such engines directed tothe solution of various problems arising from thermal distortions anddamage in service. Illustrative problems contemplated by the presentinvention include warping and cracking of the cylinder head or block,poor valve seating under heated and thermally distorted runningconditions, burning of valve seats and necessity for frequent valvegrinding, incomplete fuel combustion, and loss of fuel efficiency andhorsepower.

The present application is a continuation-in-part of our copendingapplication Serial No. 645,096, filed March 11, 1957, now Patent No.2,944,336, issued July 12,

1960, which was a continuation of our parent appliand claims novelengine structures, whether these structures result from the said repairprocess, or constitute new engine equipment. Since the novel enginestructures of the invention were initially developed for repairpurposes, they will be most conveniently disclosed herein after in thatconnection, but it will be understood that new engine structures as wellas repaired engines are broadly contemplated.

The cylinder heads and blocks of present day internal combustion enginesare subject to severe damage as a consequence of their high opera-tingtemperatures. Temperature gradients cause compressive and tensionstresses in the combustion chamber walls, and lead to cracking, bucklingand warping, distortion of valve seats, and of the cylinder head and thecylinder block. In those prior cylinder head castings, wherein the innerfire-contacted combustion chamber area is integral with cooler operatingmetal outside the combustion chamber area, there is a severe conflictbetween the tendency for substantial thermal expansion of the highlyheated firecontacted area, and the much lower expansion of the metaloutside the combustion chamber area. Severe compressive stresses are setup by the radial expansion of the fire-contacted area, resisted by thecooler portion of the casting outside the combustion chamber. The highlyheated combustion chamber wall, under this compression, crushes intoitself, so to speak, developing tremendous stresses and strains. Thiscondition is responsible for the commonly observed warping and crackingof cylinder heads.

We have also discovered that prior valve-in-head engines suffer fromvalve seats in the combustion chamber head wall being distorted fromround to oval shape as a result of radial thermal expansion forces inthe highly heated head wall, resisted by colder metal outside thecombustion chamber, resulting in poor seating of valves, loss ofcompression, fuel efiiciency and power, incomplete combustion, andburning of the valves and of valve grinding is directly attributable tothis cause.

An object of the present invention is the provision of novel enginestructures which may be utilized in the repair of thermally damagedengines, or in new engines to relieve certain thermal stresses whichlead to engine damage.

A further object is to provide an improved internal combustion enginewherein highly heated and stressed combustion chamber wall portions areseparated or isolated from surrounding cooler running portions of theengine walls, thereby eliminating the cause of the warping and crackingnormally resulting from immobility or lack of freedom of adjacentportions of the casting to stretch, expand, con-tract and move free frombinding and constriction during alternating and continuous periods ofexposure to heat and cold.

A further object is accordingly the provision of a cylinder headstructure in which the valve seats do not warp to an oval shape duringoperation as a result of thermal expansion.

A still further object is the provision of a cylinder head structurehaving valve seats therein and wherein provision is made for improvingthe seating of the valves, and characterized further by improvedcompression, fuel efiiciency and power, and more complete fuelcombustion.

Typical application of the invention to the case of the repair of athermally damaged diesel engine cylinder head wall, with the damagebeing found in the combustion head wall over the cylinder bore, is asfollows: A portion of the original combustion chamber head wall ismilled out or otherwise excised throughout an area encompassing andoverlapping somewhat, i.e., extending outside, the combustion chamberarea. In a diesel engine, this combustion chamber area is approximatelythe area of the cylinder bore, and the excised area accordingly issomewhat larger than the cylinder bore area. A replacement or insertunit is then fabricated, including a replacement head wall, which isshaped to fit into the aperture made in the original head wall. Thisreplacement head wall is not, however, integrally joined to theremaining part of the original head wall, but merely mechanically fittedtherein, and it is a preferred and important feature of the inventionthat this replacement head wall be so mechanically fitted as to afford adegree of unrestrained radial thermal expansion when the engine isheated. That is to say, there is provided, in effect, an expansion jointbetween the replacement head wall and the opposed edge of the remainingportion of the original head wall such as a gap, slidingly overlappedflanges, or a frangible region, such that, upon thermal expansion of thehighly heated replacement head wall, it will not forcibly engage theaperture defining edge of the cooler running outside or original headwall, which is more remote from the combustion flame. Thus, compressivestrains ordinarily set up in the head wall under heated runningconditions are relieved or prevented. The strains in an ordinarycylinder head wall actually occur in a complex pattern, owing todifferential heating and temperature gradients extending in variousdirections. The described isolation of the replacement head wall fromthe remaining portion of the original or surrounding head wall preventsthermally induced strain transmission across the joint therebetween, andthereby relieves the strains in each. There is thus removed a primarycause of the fractures, warpage and buckling that necessitated therepair job, so that the engine is not subject to recurrence of the sametype of damage. In this connection, in view of the damage preventioncharacter of the replacement unit, such a unit may also be used in newengines, and thus becomes an original insert unit rather than areplacement.

The construction as thus described results in freedom for thermalexpansion of the flame-contacted insert wall in all radial directions,with the result that roundness of the valve seats is preservednotwithstanding thermal expansion, and valves continue to seat properlyunder heated running conditions.

Between the replacement head wall and the top surface of the cylinderwall, around the cylinder wall, is placed a sealing gasket; which is eflective to hold engine compression. This gasket may also extend under thejoint or gap between the replacement head wall and the remainder of theoriginal head wall.

The replacement or insert unit is also equipped with means by which itis held down in position against explosion pressure, and may includealso centering means cooperating with the cylinder head, new port tubes,which coact with the original cylinder head, and new valve seats andvalve guide support structure, it being understood that the originalvalve seats and valve guide support structure, as well as port tubes,are cut away along with the removed portion of the cylinder head wallwith which said parts were integral.

Various additional objects and advantages, as well as the broad andspecific nature of the invention itself, will appear and be described inthe course of the following detailed description of a number ofillustrative embodi merits of the invention, reference for this purposebeing had to the accompanying drawings, in which: FIGURE 1 is a planview of a high compression valve-in-head cylinder head taken on the line1-1 of FIGURE 2', showing in dashed lines the areas of the cylinder headwall to be cut away in accordance with the invention;

FIGURE 2 is a side elevational view of the block and cylinder head ofthe engine of FIGURE 1, with parts being broken away to show underlyingparts in section; and showing the original head after cutting awaycertain parts thereof, including an area of the combustion chamher headwall, valve seats and valve guide support structure, and port tubes, andinstallation of a replacement unit therein;

FIGURE 3 is an enlarged view of a portion of the cylinder head ofFIGURES 1 and 2, shown after installation of the replacement unit;

FIGURE 4 is a section taken on broken line 4-4 of FIGURE 3; 7

FIGURE 5 is a transverse section taken on line 5-5 of FIGURE 4;

FIGURE 6 is an elevational view of the replacement unit of FIGURES 2-6;

FIGURE 6a shows a modified form of replacement unit;

FIGURE 7 is a transverse view through a cylinder head showing analternative form of the invention;

FIGURE 8 is a fragmentary view showing a modification of FIGURE 4;

- FIGURE 9 is a side elevational view, with parts broken away to showunderlying parts in section, of another embodiment of the invention;

FIGURE 10 is a section on line 10-10 of FIGURE 9; a v s FIGURE 11 is aview showing the replacement unit of FIGURES 9 and 10;

FIGURE 12 is a sectional view of a modification of a portion of FIGURE11;

FIGURE 13 is a side elevational view of the cylinder head side wall ofFIGURE 12;

FIGURE 14 is a sectional view through the cylinder head of an engineshowing another embodiment of our invention; l 8 FIGURE 15 is a sectionon line '1'5-15 of FIG- URE l4; a

FIGURE 16 is a perspective view of a portion of the replacement top wallof the cylinder head of FIGURES 14 and 15;

FIGURE 17 is a bottom plan view of a replacement cylinder head wall ofanother embodiment of the invention, being taken on line 17-17 of FIGURE18;

FIGURE 18 is a transverse sectional view through a cylinder head andreplacement unit in accordance with the invention;

FIGURE 19 is a perspective view of the replacement unit of FIGURE 18;

FIGURE 20 is a detailed section taken on line 20-20 of FIGURE 17;

FIGURE 21 is a detailed section taken on line 21-21 of FIGURE 17;

FIGURE 22 is a detailed section taken on line 22-22 of FIGURE 17; M

FIGURE 23 is a detailed section taken on line 23-23 of FIGURE 17; I

FIGURE 24 is a detailed section taken on line 24-24 of FIGURE 17; I

FIGURE 25 is a bottom plan view of the cylinder head of an L-headengine, showing certain thermally damaged areas, and showing theoutlines of proposed replacement units;

FIGURE 26 is a section on line 26-26 of FIGURE 25, showing a replacementunit installed in the cylinder head; V g 7 FIGURE 27 is a section takenon line 27-27 of FIGURE 26;

FIGURE 28 is an elevational view of the replacement unit of FIGURES 26and 27;

FIGURE 29 is a bottom plan view of an L-head engine cylinder head, withreplacement units installed;

FIGURE 30 is a section on line 30-30 of FIGURE FIGURE 31 is aperspective view of the replacement unit of FIGURES 29 and 30;

FIGURE 32 is a section on line 32-32 of FIGURE 29;

FIGURE 33 is a plan view of a portion of the cylinder head on anoverhead valve internal combustion enengme; I I

FIGURE 34 is a section taken on broken line 34-34 of FIGURE 33;

FIGURE 35 is a side elevational view of the cylinder head of FIGURE 33,viewed from the port side thereof;

FIGURE 36 is a detailed section taken from FIG- URE 34; I

FIGURE 37 is a front elevation of the subject matter of FIGURE 36;

FIGURE 38 is an exploded elevational view of the replacement unit ofFIGURES 33 to 35;

FIGURE 39 is a plan view of a portion of a cylinder head wall andreplacement insert showing various means of securing the latter withinthe former;

FIGURE 40 is a plan view of a cylinder head wall showing various formsof expansion joints between the heated and cooler areas of the wall;

FIGURE 41 is a detailed section on line 41-41 of FIGURE 40;

FIGURE 42 is a detailed section on line 42-42 of FIGURE 40;

FIGURE 43 is a detailed section on line 43-43 of FIGURE 40;

FIGURE 44 is a vertical section through another embodiment of theinvention, taken as indicated by line 44-44 of FIGURE 47;

FIGURE 45 is a perspective view of the insert unit of the embodiment ofFIGURE 44;

FIGURE 46 is a perspective view of a packing ring of the embodiment ofFIGURE 44;

FIGURE 47 is a section taken on line 47-47 of FIGURE 44;

FIGURE 48 is a side elevational view, with parts broken away, of theembodiment of FIGURE 44, incorporating, however, a modified securingmeans;

FIGURE 19 is a section taken on the broken line 4949 of FIGURE 48',

FIGURE 50 is a perspecive view of a spring member taken from FIGURES 48and 49;

FIGURE 51 is a plan view of another illustrative embodiment of theinvention;

FIGURE 52 is a section taken on the broken line 52-52 of FIGURE 51; and

FIGURE 53 is a view similar to a portion of FIG- URE 52, but showing afurther modification.

Reference is first directed to that embodiment of our invention shown inFIGURES 1-6, inclusive. It will first be assumed that a repair job for adamaged engine is in contemplation, and it will later be pointed outthat the structures described may also be incorporated in new engines.

The numeral 49 indicates a high compression diesel engine typevalve-in-head cylinder block to which is secured cylinder head 50 withgasket 51 inserted between the block and head, both of which areprovided with the usual valves, ports, fastenings and other necessaryparts. Head 50 is a usual hollow casting having spaced upper and lowerhead walls 50a and 58b, and the space inside the head is supplied withcoolant, in the usual manner.

The numeral 52 indicates the usual ports and 53 shows valve springs withan injector connection indicated by 54. In the block 49, a cylinderbarrel is shown at 55 with a piston 56 located therein adjacent to thecylinder head surface 57, all of which define the combustion chamberproper indicated at 58.

In the original head wall 50b of head 54% are shown various damagedareas such as injector inlet cracks 59, injector to valve seat cracks60, valve seat cracks 61, valve seat to valve seat cracks 62, and at 63a crack occurring in the area between the valve seat and the injectorinlet. At 64 are shown pits which result from the combination ofcombustion and water. The effects of distortion are indicated by anout-of-round valve seat at 65 and at 66 is shown a burned valve seat.Exaggerated illustrations of warpage are indicated at 67 for the headand at 68 for the block.

In repairing the damaged areas, portions of head wall 50b are excisedalong various shaped outlines, to be replaced by presently describedreplacement units, such as along the irregular outline shown by 69 orthe square as at 70 and the circular at 71, all of which shapes may beused singly or in combination as required to produce the cut-out mostsuitable to the type of damage being repaired. It will be observed thatthe replacement outlines in each case encompass, with some overlap, thecombustion chamber 58. Upper cylinder head wall 50a is also formed witha presently described opening to receive a presently described portionof the replacement unit. FIGURES 2-5 also show the original valve guidesupport structure, as well as port tubes, to have been cut away alongwith the removed portion of the original head wall, so as to accommodatethe replacement unit now to be described.

Numeral 72 indicates a replacement unit which is introduced through theopening made in the bottom wall 5% of the cylinder head. Thisreplacement unit includesat the top, a mounting plate 73, formed with anunthreaded centeringboss 74, received and leak-proofed, as by sealinggasket 76, in aperture 75 cut through the top wall 50a of cylinder head5%). Mounting plate 73 engages and is held down by the underside of wall50a, and machine bolts 77 secure it thereto. At the bottom, replacementunit 72 is provided with head wall 86, fitted, as presently described,into the opening made in head wall 50b, wall 86 being integrally formedwith mounting plate 73, as shown.

The valve guide tube 78 is surrounded and positioned by valve guidestructure 79 forming an integral part of the replacement unit casting,which casting also includes integral valve port tubes 80 structurallyseparated and I and overlapping ledges or flanges 86b and 50d,respecspaced from one another above their integral juncture with wall86, as shown. These port tubes are here shown to have, at their outerends, connector bells 81 within which are tightly secured sleeves 82extending through the original side wall of cylinder head where they aresecured with sealing gasket or O-rin-gs 83 under sufficient pressure toprevent leakage, by adjustable gland nuts 84. This gland structureaffords a sliding joint for the sleeves 82, to accommodate thermalexpansion of the port tubes, and thus relieve stresses otherwise set up.

Valve seats 85 are provided in replacement unit head wall 86, which isported into communication with porttubes 80.

The periphery of replacement unit head wall 86 is provided with what maybroadly be termed an expansion joint or jointure 87 at its juncture withthe edge of original head wall 50b that defines the opening cuttherethrough, as heretofore described. This joint 87, in the embodimentof FIGURES 1-5, is so designed as to accommodate sliding movement ofwall 86, relative to wall Sill), as the former expands to a greaterdegree than the latter as the engine heats up. embodiment, the opposedperipheral edges of wall 86 and wall Stib are formed with complementarystep grooves 86a and Site, respectively, thereby forming projectingtively, of which the flange 50:! overlies and slidablyengages the flange8612. This arrangement causes the re-' placement unit head wall 86 to beheld down, in part,

by the wall 50b against the force of explosions occurring in thecombustion chamber. The replacement unit is also held down by the upperwall of the cylinder head in engagement with replacement unit mountingplate 73. To permit the described sliding action, small clearancespaces, typically about .050 inch, will be understood to exist betweenthe forward edge of each of said flanges and the bottom of the grooveinto which it is received when the engine is cold. In the drawings, theparts are illustrated in the heated or running condition of the engine,with the wall 86 thermally expanded, and the clearance spaces referredto will be understood to have become substantially closed, owing to thehigher running tem perature of wall 86 relative to wall 50b.

- Under and inside of the described sliding jointure and extendingentirely therearound, i.e., disposed on at least the inner side of theexpansion joint between walls 50-b and 86, and located between walls 50band 86 above and the top of the engine block below, is compressionsealing gasket 51 which serves to seal against leak of enginecompression.

The injector tube is mounted in apertures 88 and 89.

Attention is directed to the fact that the rim portion of the combustionchamber wall 86 terminates shortly outside the circumference of thecylinder bore, and, of course, of the combustion chamber. The wall 86 isthus separated from any side walls contacted by coolant, only its uppersurface being contacted thereby. Also, this rim portion projects beyondthe circumference of the cylinder bore without any substantialthickening or peripheral re inforcement, so that the entire rim of wall86, outside the cylinder bore, will be heated by conduction from theinner fire-contacted portion thereof to substantially thetemperature ofthe latter and will thermally expand radially in all directionscommensurately with the thermal expansion of the fire-contacted area ofthe wall 86. It will be seen that the entirety of the head wall 86 as soformed will run relatively hot, and will be subject to relativelyuniform thermal expansion.

The method of engine repair represented by FIGURES 1-6 is as follows:First, the thermally damaged area of the original cylinder head Wall 50bis cut away or'ex-. cised, along a line encompassing, and spacedsomewhat outside, the area of the combustion chamber. Other portions ofthe original structureintegral with the removed In the presentillustrative 7 portion of the head wall are removed, so that the headthen appears as in FIGURES 4 and 5. An aperture 75 is cut through thetop wall of the cylinder head for the boss 74 of the replacement unit.At the time the cylinder head is thus opened up, it may be desirablycleaned out, sand blasted, and treated with rust inhibitor. Areplacement unit is then fabricated, having replacement head wall 86 forthe cut-away portion of the original head wall, and this replacementhead wall is so designed as to have a sliding, expansion joint type offit with the opening left in the original head wall. The replacementunit as described above is then installed with the sealing gasket 51 inplace, and secured, as by screws 77. As described above, thisreplacement unit also includes new valve seats, valve guide supportstructure, and port tubes, the latter being fitted into the originalside wall of the head. The repaired construction, which thus affords atwo-part head wall, with an expansion joint between the parts, is strongand leak-proof against engine compression. The unit is held down by theoverlapped flange construction at the jointure 87 and by the topcylinder head wall in engagement with mounting plate 73. Moreover, thereplacement organization is designed to withstand warping and distortionof the very kind that is responsible for most repair jobs of the kindhere in question, for the reason that the replacement head wall 86 hasbeen furnished with a capability for equal thermal expansion in allradial directions relative to the remaining portion of the original headwall 50b. The replacement head wall or wall part 86, directly coveringthe combustion chamher, is subject to far greater heating than is thewall or wall part 50b outside the direct limits of the combustionchamber. By the sliding jointure provided, the higher temperature wallpart 86 is permitted free and therefore equal thermal expansion in allradial directions, without forcibly abutting directly against theopposed edges of wall part 50b, and hence without setting up compressionstresses in either or both of walls or wall parts 86 and 5%, withconsequent inevitable warping, buckling, and ensuing distortions, aswell as actual fractures, and also without causing the valve seats to bedistorted into an oval shape, such that the valves will fail to seatproperly thereon. By referring to FIGURE 4, it may be seen that as thewall 86 expands radially when heated, the two port tubes 80, beingstructurally separated above the wall 86,

will. be spread apart: a slight distance, It will be seen:

that the temperature at the juncture of the port tubes with wall 86 willbe that of wall 86 and that the operating temperature will beprogressively lower in the up ward direction through the port tubes 80and into the valve guide structure 79 and frame or mounting plate member73. However, owing to the integral construction of members 86, 80, 79and 73, heat conduction up these members is maximized, and some degreeof outward thermal expansion occurs throughout these portions of thecasting 72, though, of course, being progressively less at higher andhigher levels. The radial thermal expansion of the wall 86 thus tends tophysically bend the port tubes 80 and the valve guide structures 79 veryslightly outward, but at the same time, the heating of the integralstructure 72 up to the level of the plate 73 causes the valve guidestructures 79 to spread somewhat apart, so that good alignment of thevalve guides with the valve seats is preserved, This result is proved bylong life of valves, valve seats, long periods between necessary valvegrindings, and improved fuel efficiency and power. It has also beendiscovered that the repaired engine, or an engine witha new cylinderhead constructed as described, develops increased horsepower, and alsoappears to more completely burn its fuel. The black smoke, usuallyobserved at, the exhaust, disappears. This may be owing to maintenanceof better compression due to better valve seating, or to hotter runningcombustion chamber walls. Apparently, the heatof the engine is morefavorably utilized.

Troubles of the kind causing the necessity of the repair job are thusremoved. Further, insofar as valve seating is concerned, the repairedengine is far superior to the original engine. The structure describedis desirable and intended for new engine constructions, as well asrepair jobs. When used in new engines, the thermal stresses described asresponsible for warping, fracturing, and poor valve seating, areprevented at the outset, and the necessity for repair jobs, includingfrequent valve grinding, owing to the results of unrelieved stresses is,therefore, avoided.

As an alternate construction to the one-piece replacement, the numeral(FIGURE 6a) indicates a modified form of replacement comprising headwall 90a, and integral port tube 91, connecting bell 92 and centeringboss and valve guide housing 93. The replacement includes an auxiliarymounting plate 94 having aperture 95 for the centering boss and valveguide housing 93, and provided with a plurality of reinforcing legs, rodor studs 96 Which bear upon the top of head Wall 90a to support andtransfer the explosion stresses to the top wall or other suitableportions of the cylinder head.

In FIGURE 7 is shown a modified embodiment of the invention. Here, theentirety of the bottom wall of the cylinder head has been removed as afirst step of a repair procedure. The cylinder head is thus betteropened up to facilitate cleaning. In. its place is installed a newbottom head wall 102, furnished with holes to receive the usual cylinderhead studs, not shown. The new bottom head wall 102 has apertures 10-3over the several cylinder barrels of the engine, and understood, as inFIGURES 1-6, to encompass and be somewhat larger than the cylinder bore(or combustion space thereover). The replacement unit, generallydesignated by numeral 98, includes mounting plate 98a, similar to thatused in FIGURES l-6, valve guide members 98b, port tubes 99 providedwith sealing gaskets or O-rings 100 tightly secured by adjustable glandnuts 101, in which the tubes 99 may slide to accommodate thermalexpansion, and replacement head wall 104 integral with port tubes 99,received in aperture 103. A removable centering boss 106 is receivedinto aperture 106a, cut through the top wall of the cylinder head. Anarrow gap entirely separates and isolates the replacement head wall 104from the defining edge of the aperture 103 in the replacement bottomhead wall 102, thus providing for thermal expansion of wall 102 withinaperture 103. As before, the drawings show the engine in its heated orrunning condition, with the said gap 105 substantially closed. It willbe understood, however, that the relationships are made such that, withthe engine heated, and replacement head wall 104 at higher temperaturethan cylinder head bottom wall 102, substantial compressive stresses,owing to differential expansion, are not transferred from wall 104 towall 102.' As in the embodiment of FIGURES -6, a compression sealinggasket 107 is installed underneath and inside the expansion joint formedbetween the walls 104 and 102, effecting a compression seal to the topsurface of the cylinder block.

FIGURE 8 shows a modification of a portion of FIG- URES 1-5, similarparts having like reference numerals. The mounting plate 73 of FIGURES1-5 is here divided into two mounting plates 73a and 73b, each integralwith one of the port tubes 80 and valve guide structure 79'. Themounting plates 73a and 7322 are flush with the underside of top wall50a, and valve guide tubes 78 are fitted with annular clearance inapertures 75. Ring seals such as 750 seal against coolant reaching theapertures 75. The mounting plates 73a and 73b are designed to shiftlaterally, that is, spread apart relative to one another, as the insertunit heats up and expands, and therefore are not fastened to the topwall 50a of the casting by screws or bolts. To facilitate such movement,bearingballs 73c may be installed, as indicated, between members 73d and73b and top head wall 50a. These bearing balls take the load, and headwall 50a does not exert pressure on members 73a and 73b, exceptingthrough these bearing balls, By this provision, the port tubes and valveguides are free to spread apart with thermal expansion of insert headwall 86, assuring perfect alignment of valve guides with valve seats atall times.

FIGURES 9-13 show an embodiment of the invention in which, in additionto excising a damaged portion of the original head wall of the cylinderhead, the side wall of the original head, through which the engine portsextend, is also removed, and in which the replacement unit includes areplacement side Wall, as well as a replacement head wall.

Referring to FIGURE 10, it will be seen that the cylinder head 114 has ahead wall 122, from which a damaged area has been excised, and it willbe understood that the aperture so formed is again of a size toencompass the cylinder bore below, with some overlap, as in FIGURES 1-6.As also shown in FIGURE 10, the original side wall of the cylinder headhas been removed on the ported side. The replacement unit 108 includes anew side wall portion 109 formed with port bosses 1141, and secured inplace by machine screws, as shown. It also includes mounting plate 111,engaged and buttressed by machine screws 112, threaded through the upperhead wall, and replacement head wall 119 fits within the aperture formedin the original head wall with a clearance space-all around, asindicated at 120. Below and inside the thermal expansion joint so formedis placed compression sealing gasket 123. A port tube 117 joinswall 119,mounting plate 111 and side plate 109. A valve seat 118 is formed in thebottom of wall 119, in communication with a bore leading to port tube117. As shown in FIGURE 10, a centering plug 113 is seated in a socketin the top of mounting plate 111, being threaded in a bore formed in thetop wall of cylinder head 114, and valve guide 115 extends through thiscentering plug and through plate 111 to protrude into the passage abovevalve seat 118.

FIGURES l2 and 13 show a modification of FIG- URE 10, wherein the porttube 124 is fitted into and slidingly extends through a port boss 126 ona separate removable side plate 125, a gasket or seal ring 127 and glandsleeve 128, sealing the port tube against leakage.

The procedure involved in making a repair according to FIGURES 9l2 willbe evident from the foregoing. The expansion joint, in this instance anopen gap 120, isolates the hot region 121 from the lower temperaturearea 122, as before, permitting unrestricted thermal expansion of thereplacement head wall 119 without transferring stress to the wall 122,and so avoiding warping and buckling strains in both members. Aneffective compression seal is again afforded by the gasket 123. As inthe cases instanced hereinabove, the construction of FIG- URES 9l3 lendsitself to new engine structures, as well as to the repair of damagedengines. In either case, damage to the engine by reason of thermallyinduced stress differentials between the highly heated region 121 andthe less highly heated region 122, as well as distortion of valve seats,are prevented.

FIGURES 1416 show an alternative embodiment, in-

tended as original engine structure. The insert unit, designatedgenerally by numeral 129, is placed within head 135, which has aremovable top wall 130, fastened to the balance of the head by screws131 reaching down and threaded into the cylinder block. Top wall 130 isprovided with apertures 133 for positioning bosses 132 on the insertunit, O-ring seals 134 being shown for sealing purposes, and the insertunit has an upper plate portion 129a which is engaged by the removablewall 130. The insert unit has a lower head wall 147, provided with asliding, overlapped type of thermal expansion jointure 145 with thelower wall of the cylinder head, similar to that described in connectionwith FIGURES 1-6, excepting that in this case the projecting flange onthe head 10 Wall 147 overlies a complementary flange on the lower wallof the cylinder head, so that the insert unit is in this instanceinstalled from above. A compression sealing gasket 146 is used, as inearlier embodiments.

Valve guide 136 is surrounded by casting portion 137 forming a part ofinsert 129. Port tubes 138, also a part of insert 129, are provided witha threaded connector bell 139 for threaded reception of connectorsleeves 140 which are provided with a sliding fit through sealing gasketor O-ring 141 under pressure from adjustable gland sleeves 142 in portbosses 143. Valve seats 144 are provided in insert wall 147. An injector149:: is inserted through aperture 149 in removable top plate 130 andthrough aperture 148 in insert wall 147.

FIGURES 17-24 show further modifications of the invention,illustratively of the type wherein the original bottom wall of thecylinder head is removed, and applicable also in new engines. In thiscase, the replacement or insert unit 150 includes a plate or Wall 151which replaces the entire original bottom wall of the cylinder head.This replacement unit includes mounting plate 154 underlying and engagedby the top wall of the cylinder head, a valve seat 156 in wall 154, acentering boss 175 fitted and sealed at 177 in an aperture cut throughthe top wall of the cylinder head, an injector aperture 176 in which theinjector 176a is received and sealed, a valve guide portion 153, andport tube 170. The port tube 170 is provided with a flange 171 forfastening to port boss 173 by means of screws 172, a sealing gasketbeing used at 174-.

The plate or wall 151 is divided into two parts 160 'and 161 by athermal stress relieving jointure, several illustrative forms of whichare shown in FIGURE 17 and FIGURES 2024, inclusive. This jointure willbe understood to again encompass and extend somewhat outside thecombustion chamber area over the cylinder bore (not shown), and hasunder and extending inside it, a compression sealing gasket 167. The twoparts 160 and 161 of wall 151 may be integrally connected across thejointure, or separated therefrom, according to the specific jointdesign.

At 162 in FIGURE 20, the jointure comprises a flexible, imperforate foldor loop 162, permitting radial expansion and contraction of highlyheated inner part 161) relative to the cooler outer part 161.

In FIGURE 21 is shown a jointure comprising frangible webs 163 across acircumferential slot 163a. This structure permits a degree of expansionand contraction of inner part 160 relative to outer part 161; but ifdeformation is excessive, the frangible webs 163 may fracture, with noharm to the engine, the fracture being confined to a predeterminedlocation at which no engine damage requiring repair has been done.

In FIGURE 22, the parts 160 and 161 are separated by a circumferentialclearance space or gap 164accom? modating expansion and contraction ofinner part 160.

In FIGURE 23, the jointure comprises a deep circumferential groove 165,leaving a thin, frangible connecting portion which may fracture uponbecoming highly stressed. As in FIGURE 21, such fracture occurs along apredetermined line where no harm to the engine is done.

Finally, FIGURE 24 shows a frangible jointure comprising a plurality ofclose spaced drill holes 166.

By way of further illustration of stresses set up in the head wall orplate 151 during heating and cooling of the engine, we have, in FIGURE17, represented at 158 thermal tension stresses acting across thejointure, and at 159 thermal compressive stresses, these developingowing to the fact that the inside part 160, directly exposed to theflame, is heated to much higher temperatures than the outside part 161,which is heated only by conduction, and in addition is liquid cooled,causing greater alternate and continuous expansion and contraction ofpart 160 as compared with part 161. The heated part 160 opposes thecooler part 161. The jointures shown are capable of 11 accommodating theexpansion and contractions of part 160, and relieve the stressesrepresented at 158 and 159.

In FIGURES 2528 are shown a replacement, or new construction, for thecylinder head 208 of an L-head internal combustion engine. Referring toFIGURE 25, spark plug apertures are indicated at 209. At 210 isrepresented a transverse crack due to a longitudinal strain, at 211 alongitudinal crack owing to a transverse strain, and at 212 a transversecrack extending inwardly from spark plug aperture 209. At 213 and 214are shown, respectively, single and two cylinder replacement or insertunits. Referring now to FIGURES 26 and 28, the replacement or insertunit 213 is provided with peripheral head wall flange 218, with which isintegrally formed combustion chamber head wall 218a. Joined with theupper portion of combustion chamber head wall 218a is spark plug housing215, which protrudes through and is sealed, as at 217, within anaperture formed in the top wall of head 288, thus functioning as apositioning means. The flange portion 218 of the replacement unit isprovided with a Sliding, expansion jointure 219 with the opposed walledge left when the damaged area of the original head wall was excised.It will be understood, inline with discussions of earlier embodiments,that the first step in the procedure, in the case of a replacement, isto excise the original, damaged head wall along such an outline as 213.The sliding jointure is here shown as of the above-described overlappedflange type, with free? dom for thermal expansion of the replacement bysliding action of the jointure flanges on one another to take uporiginally provided clearance space. An underlying com? pression sealinggasket is used, as at 220.

FIGURES 29-32 show a modification of the L-head engine cylinder head ofFIGURES 2528. Here it may be assumed that an entirely new cylinder headis provided, assembled from separate side and top wall com; ponents.Alternatively, the damaged lower head wall of the original cylinder headis also completely removed, leaving only the side wall 221 of theoriginal cylinder head. An insert unit 225 is provided, and includes acombustion chamber defining wall 225a, with a marginal fiange 225bhaving its lower edge 238 in engagement with cylinder block 23 2. Asindicated, this edge encompasses the cylinder bore below, and the entirelength of the com bustion chamber (FIGURE 32). Head plate 222 isprovided, resting down on the upper edge of the side Wall 221, and asealing gasket or O-ring 223 seals the juncture therebetween. Head plate222 is held down to block 232 by means of studs 224. The insert unit isprovided with posts 228which are engaged by plate 222 for purpose ofadequate support of the replacement unit against explosion pressure. Theinsert unit is further provided with spark plug housing 226, which isperipherally engaged by plate 222, and sealed at 229, an access hole 227for the plug being formed in plate 222. A compression sealing gasket 231underlies the lower insert edge 230. It will be seen that the marginalwall portion or flange 225b is spaced by an expansion gap from thecylinder head side wall 221, and therefore is unconfined by and isolatedfrom the latter, so that it is free for expansion and contractionmovements.

FIGURES 33-38 show a replacement, or new construction, for a head wallof an overhead valve internal combustion, spark plug engine. The lowerwall of the original cylinder head 233 is cut away on an outlineencompassing the cylinder bore in the block 253. The replacement orinsert unit 235 has at the top a mounting plate 236 adapted to beengaged by the underside of the top wall of head 233, and formed withcentering boss 239 received and sealed, as at 241, in aperture 240formed in the top wall of the head. Extending downwapdly through thiscentering boss 239', and opening into port tube 242 in a position overvalve seat 252, is a valve guide tube237. The port tube 242 joinsthereplacement wall 235a that definesthe new combustion chamber, and

this wall 235a is formed with a peripheral flange 235b that is fitted inthe aperture in the remaining portion of the original head wall, using,in this instance, a sliding expansion joint at 250 of the type describedin connection with FIGURES 1-6, a compression sealing gasket 251 beingused, as shown. Port tube 242 is formed with an internally threadedconnector bell 243, into which is threaded connector sleeve 244 held insliding but leakproof condition by sealing gasket or O-ring 245 andadjustable threaded gland sleeve 246 threaded into port boss 249. Sleeve246 is preferably formed with cogs 247 for tightening by means of anadjusting tool or pin through holes 248 in port tube boss 249. A sparkplug housing 254 is threaded through the side wall 235a of thereplacement unit, and has a tubular external portion 254a whichprotrudes through an aperture 256 formed in the side wall of cylinderhead 233, being sealed therein by O-ring seal 257.

In FIGURE 39 are shown various means of aligning a replacement orreconditioned head wall 258a in a cylinder head wall 258. The wall 258amay be of any shape, though here shown as circular, being fitted intothe circular aperture 259 which has been formed in original head wall258. Valve apertures are shown in wall 259a at 260, and an injector portat 261. An aligning and securing pin is illustrated at 262, inserted inan aperture half formed in wall 258 and half formed in wall 258a. At 263is indicated a screw, threaded half int wall 258 and halfinto wall 258a.A spot welded juncture is indicated at 265, and a brazed joint at 264.Be? tween the fastenings, the walls 258 and 258a may be unconnected.These spaced fastenings permit limited working of the wall 258 a withinthe wall 258, thus affording some flexibility and accommodation forthermal expansion of the member 258a relative to member 258.

FIGURES 4043 show various expansion joints formed in the lower head wall266 of a cylinder head, between the highly heated regions directly overthe cylinder, and the cooler regions outside thereof. The originalheadwall is formed with bores 267 for holding the unillustrat-ed headcasting above the wall 266, and the wall 266, tightly down to the block,also not shown. Wall 266 is shown furnished with valve apertures 268,injector aperture 269, and air inlet aperture 279. The arrows 270 and271 diagrammatically represent thermal tension and compressive stresses,respectively, occurring acrossthe regions between the highly heated andhighly stressed central area 272, over the cylinder bore, and the coolerand less stressed outer area-3273. The expansion joints illustratedrelieve these stresses, which are developed as the engine heats andcools. The joint at 274, consisting of a line of perforations, connectedby web portions capable of easy fracture, forms a frangible type ofjoint, which has certain inherent flexibility to accommodate expansionand contraction, but which will fracture upon occurrence of substantialstresses. The fracture that may occur is along a predetermined line in apreferred location, such as, will not put the engine out of'runningcommission. An alternative groove type joint is,indicated at 276, thebottom of which comprises a frangible web 277, and has propertiessimilar to the joint discussed immediately above. At 278 is shown athrough slot, which may extend entirely around the inner wall region272, isolating it completely from the outer wall region 273. In otherwords, by this construction, the Wallis separated into inner and outerwall portions, separated by a clearance or gap, and permittingsubstantial thermal expansion of the inner wall portion relative to theouter wall portion without abutment taking place, with resultingcompressive stresses in the members. These joints will be understood tobe equipped with sealing gaskets such as disclosed in earlierembodiments; and the inner wall member 272 will further be understood,in practice, to be furnished with any suitable holddown means, such asdisclosed in connection with earlier 13 embodiments, and such as willmaintain it in position notwithstanding complete severance from theouter wall member 273.

In FIGURES 44-49, we have illustrated a valve-inhead diesel engine head290, closely resembling a known commercial head, but modified to acceptan insert unit 291 in accordance with the invention. In these figures,FIGURES 48 and 49 show the same head and insert unit as FIGURES 44-47excepting only for a modified means for lateral securement of the insertunit in the head, and like reference numerals are used throughout.FIGURES 48 and 49 are, accordingly, illustrative, excepting forsecurernent means, of certain details of the structures of FIGURES44-47. A conventional block is shown at 292, having cylinder bore 293and coolant jacket 294. Head 290 is held down to block 292 by usualstuds 295, a gasket 296 being used therebetween.

Head 290 has top wall 297, side walls 298 and bottom wall 299. Thebottom wall 299 has been milled out to afford an opening 300 thereinexceeding the diameter of the cylinder bore by a small margin, and thisopening 300 is deepened at the bottom by a step groove 301.

The insert unit 291 comprises a unitary casting which is introduced intothe interior of the head through the bottom opening 300. The castingincludes a bottom wall 302, designed to serve as the top, defining wallof the combustion chamber and this bottom wall is preferably ofsubstantially the same thickness as wall 299, and is preferably ofsubstantially the same thickness throughout. The periphery of this wall302 is step grooved, as at 303, so as to be complementary to thestep-grooved inner periphery of opening 300. Clearance spaces, of theorder of about .050 inch are provided between the projecting tongue 304of wall 302 and the bottom of groove 301, and between the projectingtongue 305 of wall 299 and the bottom of groove 303, as indicated. Thetongues 304 and 305 interengage vertically, thus limiting upwardmovement of unit 291, and aiding in the support of the latter againstcombustion pressure.

Formed in insert bottom wall 302 are valve seats 308 for overhead valves309, and integral with and rising from wall 302, inwardly of theperiphery thereof, and around each of seats 308, is port tube and valveguide supporting structure designated generally by numeral 310. Thisstructure includes a top 311, which engages upwardly against a machinedundersurface of the top wall 297 of head 290. Extending downwardly fromtop 311 in axial alignment with valve seats 308, are tubular bosses 314which tightly receive the lower portions of guide sleeves 315 for valvestems 316. Sleeves 315 project through and above top head wall 297through apertures 317 therein, and have, above wall 297, shoulders 318for valve springs 319. As clearly shown, the shoulders 318 are of lesserdiameter than apertures 317. Surrounding sleeves 315 immediately belowshoulders 318 and above the top surface of insert top 311 are packingrings 320. These rings 320 are received freely in apertures 317, andtheir inner diameters are slightly greater than the diameters of sleeves315, whereby the sleeves are capable of slight lateral shifting withinthe rings and therefore relative to head top wall 297. Rings 320 aresealed within apertures 317 by O-ring seals 322, and to insert top 311by O-ring seals 323.

Above each of valve seats 308 is a port tube passage space 325 (FIGURE47), which joins port tube passage 326 located immediately outwardlythereof. These port tube passages 326 are defined by port tube members327 terminating unidirectionally in end faces 328 which are in a commonvertical plane, and which are adapted for coupling to later-describedport tube members which are integral with head 290. The port tubemembers 327 integrally merge at the top with top member 311, and at thebottom with bottom wall 302. They also include curved wall portions 329enclosing the aforementioned spaces 325.

It is to be observed that the wall portions 329 of the two port tubes327 are separated and spaced from one another, affording coolantcirculation space 330 there- 'between. This separation of the two porttubes also permits a small but desirable and important separativemovement therebetween as the bottom wall 302 becomes highly heated andexpands during running of the engine.

Bottom wall 302 of insert unit 291 is furnished, immediately in front ofand between valve seats 308, with an angularly disposed threaded orifice330 to receive the threaded extremity of a generally cylindricallyformed precombustion chamber and fuel injection barrel 332. This barrel332 will be understood to contain both a precombustion chamber and afuel injector, of conventional type, Whose internal details need not beshown. It is generally representative of any of various auxiliarydevices which may be carried by the insert unit, such as precombustionchambers, fuel injectors, glow plugs, or the like, and which, accordingto the invention, passes through the upper wall of the head, withaccommodation for lateral shifting relative thereto. For the purpose ofclaims, the unit in question is referred to broadly as an auxiliarybarrel. This barrel 332 is installed from the top through an aperture333 in top wall 297 of head 290. Reference for best illustration ofthese ports is here made to FIGURE 48, which shows the same head andinsert unit as disclosed in FIGURES 44-47, excepting only for certainlater-described optional details as regards securing the insertunit'within the head. Also as 'best shown in FIGURE 48, the head isformed with a partially cutaway cylindric wall 334 which cradles andsupports the barrel 332. At its lower end, this wall 334 engages araised pad 335 on insert bottom wall 302. Shortly above its lower end,wall 334 has an angular seat 335 which is engaged for support by afrusto-conical seat 336 on the barrel 332. Near its upper end, thebarrel 332 has a shoulder 338 of a diameter somewhat smaller thanaperture 333, and above said shoulder is a portion 340 of reduceddiameter. A packing ring 341 encircles portion 340 immediately aboveshoulder 338, and is loosely fitted in aperture 333. An O-ring seal 342in ring 341 seals to the wall of aperture 333, and another O-ring seal343 in said ring seals to shoulder 338. A retaining ring tightly mountedon the barrel confines ring 341 in position, and is set up only looselyagainst ring 341, so as to permit relative lateral shi ting of said ringon the barrel 332. The barrel 332 is thus packed in a fluid-tightmanner, but afforded the capability of slight lateral shifting relativeto head 290'.

Referring to FIGURE 44, and particularly to the righthand portionthereof, the interior of the casting is cored out to the dotted line 350to define side wall 298, and to afford coolant space, and certain webshave been provided, as indicated, including a vertical web 351 whosebottom edge is engaged by bottom wall 302 of insert unit 291.

FIGURE 44 shows also one of two parallel port tubes 354 formedintegrally with the left-hand side wall of the head and projectingupwardly to mate with the end face 328 on the corresponding port tubes327 of the insert unit, a gasket 355 being used therebetween. The entireinsert unit is secured to head 290 by means forcing its port tubes 327toward and into pressure engagement with the ends of the port tubes 354of the head. In FIGURE 49, this means is in the form of studs 354located in pairs of upper and lower longitudinally bored bosses 355 and356, respectively, threadedly engaged into unit 290 above and below theport tube passages. These studs are set up tightly, and effectivelyclose the port tube joints. In FIGURE 49, lower bosses 356 also engageand cooperate in holding down the top of lower wall 302 of the insertunit. All points of vertical engagement between the insert unit and headcomprise horizontal machined surfaces, permitting relative horizontalshifting therebetween in original installation or owing to thermalexpansion of

1. A CYINDER HEAT FOR THE CYLINDRICALLY BORDER BLOCK OF A LIQUID-COOLED INTERNAL COMBUSTION ENGINE, COMPRISING; WALLS DEFINING A HALLOW, LIQUID-COOLED CYLINDER HEAD, INCLUDING A TWO-PART WALL STRUCTURE APPLICABLE TO THE TOP OF THE BLOCK, SAID WALL STRUCTURE INCLUDING AN INNER, LIQUID COOLED BUT HOT-RUNNING WALL MEMBER OVER AND CIRCUMSCRIBING THE CYLINDER BORE IN THE BLOCK AND HAVING A FLAME-CONTACT COMBUSTION-CHAMBER-DEFINING PORTION 